This invention relates to a pulp mold for producing fiber bodies from used pulp and the like. Such fiber bodies are suitably used as packaging and shock-absorbing materials, for example, egg boxes, fruit crates, packages for industrial products. This invention also relates to the method for producing such fiber bodies.
Conventionally, in Japan, plastic and styro-foam containers have mainly been used for packing industrial products or the like as shock absorbers. However, such containers add to environmental problems since they are not biodegradable, they release hazardous gas upon incineration, and so on. Therefore, conversion to fiber containers using old pulp, which can be re-formed many times, has come to be investigated.
The conventional pulp mold having a complex structure is formed into a desired shape by joining blocks made of aluminum or the like, each block having numerous pores for water passage, and at least the molding surface of each block is covered by a wire net. Washing the mold using a shower of water at each interval of molding can prevent, to some extent, the water passages from becoming clogged. However, washing complex-shaped molds is extremely time consuming. Moreover, there are problems such as (1) the need for much time and high level of skill in the production of molds having complex shapes as described above, (2) the difficulty in eliminating unwanted marks of the joints and patterns of the wire net from the surface of the final product, and (3) the inability to form letters or minute designs since the wire conventionally used cannot produce precise edges and corners. Further, when the pores for water passage are clogged, the operation has to be stopped and the mold is washed by pressurized water.
Another type of pulp mold has been proposed in Japanese Patent Laid-Open 60-9704 by Daiken. This discloses a single layer of particles forming the molding surface, of a size chosen to provide a smooth surface. The thickness of this layer is 5-60 mm. There may be a backing plate having apertures. In actual use, this mold will clog, because the large areas of the molding layer are directly backed by unapertured areas of the plate. Backwashing is not described.
The present invention intends to solve the above-discussed conventional problems by providing a pulp mold for producing fiber bodies, which: (1) suffers little clogging of water passages, (2) can produce fiber bodies having smooth surfaces, (3) is not prone to be damaged by repeated use, and (4) can be easily produced in a short amount of time. With the present invention, the critical number of possible continuous pulp moldings can be greatly increased.
The present invention is further intended to provide a pulp molding process, a molding apparatus, and a shaped pulp article, using the above-discussed pulp mold, to greatly increase the critical number of possible continuous pulp moldings.